Field of the Invention - The present invention relates generally to a safety device which cuts off the water supply to a house or building in the event of overly high water consumption due to a leak or break in the plumbing in the house or building, and more particularly to an improved safety flow device having only three moving parts and of simple and inexpensive to manufacture construction.
Other than fire, perhaps the most catastrophic type of damage which can occur to a home or other building is damage due to water leakage from a broken or badly leaking water line. Since water supply lines may run throughout a house or other building, a leak may occur in the heart of the house or other building, and may result in extensive damage both to the structure and to the contents prior to the water supply being manually shut off.
As will be known by those skilled in the art, there exist a number of devices which are designed to control flow, and to act as a shutoff in the event of a leak. These devices generally fall into two major categories, namely the shock operated type and the flow or pressure operated type. The shock operated device is designed to operate to shut off flow in the event of a major shock, such as that of an earthquake or the like Examples of such devices are found in U.S. Pat. No. 3,747,616, to Lloyd, in U.S. Pat. No. 3,768,497, to Mueller, in U.S. Pat. No. 4,091,831, to Pazmany, in U.S. Pat. No. 4,336,818, to Dauvergne, and in U.S. Pat. No. 4,485,832, to Plemmons et al. These devices are all designed for use with gas lines, and do not address the problem of breaks or leaks in the line downstream of the devices.
The second approach, which causes a shutoff of flow in the event of an overly large flow rate or an excess pressure drop across the device, are illustrated by U.S. Pat. No. 2,659,383, to Frager, U.S. Pat. No. 4,522,229, to Van de Moortele, and U.S. Pat. No. 4,665,932, to Quenin. All three of these devices are designed primarily for industrial applications, and are large, complex, and expensive, and therefore are unsuitable for use in a home or other relatively small building. For example, the Frager device used two pistons to operate a complex camming mechanism which in turn operates a third piston to drive the shutoff mechanism. Even in the schematic depiction of the Frager patent, there are over fifteen moving parts, with the actual implementation being even more complex. The Frager device is intended for use as a primary shutoff mechanism in water mains, and simply does not have application for use with houses and like buildings.
The Van de Moortele device is a multi-purpose safety device, and cuts water off in the event of a downstream leak, the expiration of a predetermined time, or an excessive flow rate. In the schematic depiction in the Van de Moortele patent, no less than seventeen moving parts are shown, with substantially more no doubt being needed in an actual embodiment. Finally, the Quenin device is intended for use in hydro-electric installations, and functions as a shutdown valve in the event of an accident which is evidenced by a highly excessive flow rate. It is a differential amplifier device, operating using static and total pressures measured by Pitot tubes in the flow stream, and is quite complex. In addition, the Quenin device is not designed to be responsive to the situation contemplated by the present invention, namely a leak in downstream plumbing.
It will accordingly be appreciated that the devices described above are not intended for the particular application contemplated by the present invention, and as such do not represent desirable solutions to the problem addressed by the present invention. It is accordingly the primary objective of the present invention to present a solution to the problem of plumbing breaks and leaks in a house or like building. Upon the occurrence of such a break or leak in the plumbing of a house or like building, it is the objective of the present invention to immediately sense the break or leak and promptly shut down the flow of water to the plumbing.
It is also an objective of the present invention to have as few moving parts as possible, both to minimize the cost af manufacture and to make the device of the present invention as reliable as possible, with a long life expectancy without the necessity of maintenance. It must be totally reliable, with a fail-safe mode of operation to ensure reliable shutoff in the event of a plumbing break or leak even after years of use. It is also desirable that the device include means for bypassing the safety flow operation if desired, and that it function as a shutoff valve as well to allow repairs to be done on the plumbing. Further, the present invention must be both simple of construction and easy to install to enable it to be easily and quickly installable into the plumbing system of any house or like building.
The device of the present invention must therefore be simple and inexpensive of construction with a minimal number of moving parts, have an extended, highly reliable operating life, and must operate flawlessly and immediately upon the occurrence of a plumbing break or leak to shut off the flow of water, thereby preventing extensive water damage to the house or like building. It must overcome the disadvantages of the art and accomplish all of the above advantages and objectives while incurring substantially no disadvantage. Such an apparatus will represent both a highly desirable improvement in the art and a marketable and useful device.